Andy Wyenandt

This is an archive of Dr. Wyenandt's posts on the Plant and Pest Advisory.

July 19, 2014

Don’t Rely on Disinfestants for Disease Control

The hot, wet weather this past week brought with it heavy winds and rain to many areas and spikes in reports of Phytophthora blight and bacterial problems on tomato and pepper. In general, this type of weather is ideal for the development and spread of many vegetable diseases. 

By now most growers are on weekly protectant fungicide programs to help prevent disease development. It’s important to remember at this point in the season when disease pressure is high that growers stick with their standard fungicide programs.

Growers should not replace fungicides with disinfestant-type products in their weekly fungicide programs.

Remember, the disinfestants only kill what they come into direct and immediate contact with and do not offer any residual activity like fungicides do. Disinfestants should be used in conjunction with weekly fungicide programs and be applied based on specific weather events such as following rainfall or overhead irrigation or after certain cultural practices such as tying or pruning where plant injury or wounding may occur.

Filed Under: Vegetable Crops Tagged With:
July 18, 2014

More Late Blight Reported in PA

More late blight was reported in Pennsylvania this past week in Clinton, Lackawanna, and Berks Counties. The wet weather this past week as been ideal for its development across most of the mid-Atlantic region.

To date, no late blight has been reported in New Jersey on potatoes or tomato. However, all tomato and potato growers in New Jersey should be scouting and applying preventative fungicides on a regular basis.

For more information on late blight in PA see Late Blight is Spreading Across Pennsylvania.

Filed Under: Vegetable Crops
July 15, 2014

Vegetable Disease Briefs 7-15-14

  • Cucurbit downy mildew was confirmed in Wicomico County, Maryland late last week. All growers should continue to scout all cucurbit fields on a regular basis. Once harvesting is finished all fields should be disked under and or sprayed with gramoxone. Please see the 2014 Commercial Vegetable Recommendations Guide for specific fungicide recommendations. To track the progress of cucurbit downy mildew please visit North Carolina State University’s Cucurbit Downy Mildew Forecasting Center at http://www.ces.ncsu.edu/depts/pp/cucurbit/
  • Phytophthora crown rot is being reported in multiple crops. Weather conditions for the past few days have been ideal for its development.
  • There have been no new reports of Late blight in the region. To date, Late blight has been reported in Lancaster County, PA and confirmed in west central PA; on Long Island, NY and western NY.  To track late blight in the US please visit http://usablight.org/.

    • [Read more…]

Filed Under: Vegetable Crops
July 3, 2014

Controlling Cucurbit Downy Mildew

Once cucurbit downy mildew (CDM) is detected in the mid-Atlantic region (as of yesterday in Maryland) all cucurbit growers in New Jersey should begin to include downy mildew specific fungicides in their weekly fungicide programs on all cucurbit crops.

Symptoms of cucurbit downy mildew on infected cucumber leaf.

Symptoms of cucurbit downy mildew on infected cucumber leaf.

[Read more…]

Filed Under: Vegetable Crops Tagged With:
July 2, 2014

Cucurbit Downy Mildew Confirmed in Maryland 7-2-14

Cucurbit downy mildew has been confirmed on cucumber in Caroline County, Maryland.

This is the first report of cucurbit downy mildew in the mid-Atlantic region this growing season. All cucurbit growers should scout their fields on a regular, if not, daily basis. All cucurbit growers should consider switching to a preventative fungicide program that includes downy mildew specific fungicides. For more information, please see the 2014 Commercial Vegetable Fungicide Recommendations Guide.

Filed Under: Vegetable Crops Tagged With:
July 1, 2014

Vegetable Disease Briefs 7-1-14

  • Late blight has been confirmed on potato and tomato in Lancaster County, PA and confirmed on potato in west central PA (Cambria County); in potato on Long Island, NY (Suffolk County) and on potato in western NY (Erie County).  To date, no late blight has been reported in NJ. To track late blight in the US please visit http://usablight.org/.
  • Basil downy mildew has been reported in New Jersey. With current weather conditions all basil growers should scout on a daily basis and taking appropriate preventative measures.
  • Cucurbit downy mildew has been reported on cucumber as far north as central North Carolina as of 6/20. No cucurbit downy mildew has been reported in the region to date. To track cucurbit downy mildew in the US please visit http://cdm.ipmpipe.org/
Filed Under: Vegetable Crops